Addison’s Disease – Genetics Study in Portuguese Water Dogs

Portuguese water dog on a sled

Addison’s disease (also referred to as primary hypoadrenocorticism) is an immune-mediated disease in dogs and humans in which the body attacks the outer layer of the adrenal glands. This leads to a deficiency in key hormones (cortisol and aldosterone) which regulate responses to stress and water/electrolyte balance. Dogs often present with waxing and waning gastrointestinal signs, a finicky appetite, or generalized lethargy. In some cases, dogs present to veterinarians in a shock state, which can be life-threatening if the signs of Addison’s disease are not recognized promptly. Therapy for Addison’s disease is available, but requires lifelong commitment by owners with hormone replacement therapy (typically a monthly injection and daily pills).

Study Goals

Drs. Steven Friedenberg at the University of Minnesota College of Veterinary Medicine and Leigh Anne Clark at Clemson University are working to identify genetic risk factors for Addison’s disease in Portuguese Water Dogs and Standard Poodles, which are very highly related breeds. Our goal is to use this research to better understand the disease mechanism and disease triggers, and to develop a test that can help breeders decrease the incidence of the disease.

Enrollment criteria

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Affected Portuguese Water Dogs

  • Any age with a diagnosis of Addison’s disease
  • Documentation of the diagnosis with an ACTH stimulation test and an abnormal serum sodium:potassium ratio
  • Your willingness to volunteer a blood sample from your dog for genetics research
  • International submissions are welcome

Unaffected Portuguese Water Dogs

  • Minimum of 8 years of age
  • No history of Addison’s disease, or any other autoimmune disease
  • Your willingness to volunteer a blood sample from your dog for genetics research
  • Samples accepted primarily from the US and Canada due to sample shipping requirements, however samples from other countries may be accepted on a case-by-case basis

Study information

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Information for owners

  • Please contact us at [email protected] if you are interested in having your dog donate a blood sample. We will discuss with you whether your dog is a candidate for the study, and obtain the necessary medical records from either you or your dog’s veterinarian.
  • If your dog meets the criteria for the study, we will provide a prepaid shipping label for your veterinarian to send us a blood sample from your dog at our expense. You can then schedule a brief appointment with your veterinarian for a blood draw. After the visit, your veterinarian will send the blood sample to us, along with a consent form and any relevant medical records.
  • We will also send you a short electronic survey to fill out about your dog’s health history.

Information for veterinarians

If you have any clients who you think would be interested in participating in our study, or if your client has approached you about this study, the following information should be helpful.

We are studying the genetic basis of Addison’s disease in dogs. We are interested in collecting DNA samples from affected and unaffected Portuguese Water Dogs and Standard Poodles.

Affected dog inclusion criteria 

  • Flat/abnormal ACTH stimulation test
  • Pre-treatment electrolytes documenting an abnormal serum Na:K ratio
  • No age restrictions
  • Dogs can be receiving treatment for Addison’s disease (or other conditions) the time of study enrollment

Unaffected dog inclusion criteria

  • At least 8 years of age
  • No history of Addison’s disease, or any other autoimmune disease

For all dogs, we require 4-5 mL of blood in 1 or 2 EDTA/purple top tubes for isolation of DNA.

For affected dogs, we also require medical records confirming the diagnosis of Addison’s disease (ACTH stimulation test and pre-treatment electrolytes).

For unaffected dogs, we require an additional 1 mL of serum. We will run a baseline cortisol on the dog at the University of Minnesota to rule out Addison’s disease (the study will pay for the cost of this test). In some cases, if the baseline cortisol is less than 2 mg/dL, we may be able to pay for an ACTH stimulation test to definitively rule out Addison’s disease; performing the ACTH stimulation test is at our discretion.

In addition to the blood samples, owners will be asked to fill out a short electronic survey and upload a pedigree online.

If you have any clients meeting the above criteria who might be interested in donating a blood sample for genetics research, please e-mail Dr. Steven Friedenberg at [email protected] with your contact details and we will arrange a time to discuss the case. If your patient qualifies, we will send you a prepaid shipping label to send us the blood sample(s) at our expense. We will provide you with further shipping details once we ensure that your patient is a good candidate for the study.


Funding for this research is generously provided by the Portuguese Water Dog Foundation.

About the Investigator

Dr. Steven Friedenberg with poodle

Dr. Steven Friedenberg is a board-certified veterinary critical care specialist and a geneticist, and he is currently an Associate Professor at the University of Minnesota College of Veterinary Medicine. He earned his veterinary degree at Cornell University, completed his residency at The Ohio State University, and holds a PhD in genetics from North Carolina State University. He is passionate about studying canine Addison’s disease, immune-mediated hemolytic anemia, and other autoimmune diseases. He also is interested in developing novel bioinformatics and immunologic tools for the canine scientific community.